Installed the app yesterday this was my experience:

The pop-up was downloading then flashed a message:  All Done!  At that point Windows put a message on it that said it was unresponsive.  I let it run instead of ending it and then it opened a new black pop up that showed: finalising installation.   But it is very confusing because there's no indication that you have to wait and takes a while before the next thing happens. 

Suggestion:  Replace the All Done!  with Installing - please wait.

After closing it, it minimised to my hidden icons instead of closing.  I changed the setting afterwards - but would suggest you change the default to close instead - I don't personally foresee a use for it minimised like that.

While it was minimised like that it had a setting active that says prevent sleep when a game is playing - and that prevented my screen from switching off when I left my pc alone for an hour.  Please check that setting, because it shouldn't be active when the app is minimised to hidden icons - or change the default.